Hydrocarbon industry servicing fluid and methods of performing service operations

ABSTRACT

A hydrocarbon industry servicing fluid comprises an irradiated fluid that is biologically inert. The fluid may be irradiated with ultraviolet light. A method comprises performing a hydrocarbon industry service operation with an irradiated fluid that is biologically inert. The method may comprise disposing of the irradiated fluid to the environment or capturing the irradiated fluid when the service operation is complete. The method may further comprise re-irradiating the captured irradiated fluid to produce a remediated fluid, and performing a service operation with the remediated fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

FIELD OF THE INVENTION

The present invention relates generally to the use of irradiation, suchas ultraviolet light, to disinfect fluids, including water. Moreparticularly, the present invention relates to hydrocarbon industryapplications where irradiation may be used to disinfect fluids, insteadof treating fluids with chemical biocides or using untreated fluids.

BACKGROUND

In hydrocarbon industry applications, such as offshore pipelinepre-commissioning procedures and well fracturing operations, servicingfluids including seawater and fresh water may be left untreated or maybe rendered biologically inert by treating the fluids using chemicalbiocides.

In offshore pipeline applications, a water-based servicing fluid may beused to flood the pipeline during installation or to flood andhydrostatically test the pipeline once installed. During installation,the pipeline is laid on the seabed and then flooded with seawater, or inthe case of alloy pipelines, fresh water. Once a pipeline is flooded,subsea connections can then be made. In particular, divers or remotelyoperated vehicles (ROVs) physically open the pipeline and connect it toa wellhead, subsea template, or riser system, for example. When makingsubsea connections to an alloy pipeline, it is undesirable for theseawater to contact the inner pipeline surfaces because seawater maycorrode the pipeline. Therefore, the alloy pipeline is flooded withfresh water that includes a slug of gelled water at each end. As such,when the end of the pipeline is opened up for subsea connections to bemade, the gel barrier prevents seawater from ingressing into thepipeline and mixing with the fresh water. After all subsea connectionsare made, additional water is pumped into the pipeline tohydrostatically test the structural integrity of the pipeline and anyconnected components. Once installation and testing are complete, thewater contained within the pipeline is displaced and, in some cases,disposed of to sea.

At any point where water is being introduced into the pipeline, whetherin the flooding stage or in the hydrostatic test stage, this water istypically filtered and treated with a chemical biocide to disinfect thewater. The purpose of such treatment is to prevent bacteria andbiological growth from causing damage to the pipeline internal surface.However, due to environmental laws and regulations, seawater used forhydrostatic testing in a number of locations, such as the Gulf ofMexico, cannot be disposed of to sea if it contains any chemicalbiocides. Therefore, untreated seawater is used, which permits organicgrowth in the pipeline, which may constrict and/or corrode the pipeline.This can have a detrimental effect on the available flow rates of thepipeline once in service. Although discharge of water containingchemical biocides is still permitted in other parts of the world, manycountries are beginning to follow the lead of the Gulf of Mexico byprohibiting the discharge of chemical biocide treated water to seabecause such discharge may harm marine life. Therefore, a need existsfor a fluid treatment method that complies with environmentalrequirements and is not harmful to marine life if discharged to theocean.

Chemical biocides are also used during pre-commissioning procedures forpipelines installed onshore. Disposal of water containing chemicalbiocides on land is also prohibited in some environmentally sensitiveregions of the United States. In regions where no prohibitions exist,disposing of water containing chemical biocides is still undesirable inthat it may harm wildlife and contaminate underground water. Therefore,a need exists for an alternative, environmentally friendly method ofdisinfecting fluid.

Fluids treated with chemical biocides are also used in well boreservicing operations, such as fracturing a formation, for example. Theseoperations are often conducted in remote locations where water is scarceand must be transported to the well site, which is costly. Typically,the water is filtered and treated with chemical biocides to preventbacterial growth during transportation and/or storage. In a fracturingapplication, a gelling agent and other constituents are added to thewater prior to injection into the well bore. However, gel may act as afood source for any bacteria present in the fluid. Thus, if bacteria ispresent in the base water, the bacteria will eventually destroy the geland negatively impact the fracturing operation. Hence, the water isgenerally disinfected with chemical biocides before its use in thefracturing operation.

Once the fracturing operation is complete, flowback fluid recovered fromthe well bore may be stored in man-made tanks or lined pits, but it isnot disposed of to land due to the chemical biocides. This flowbackfluid containing chemical biocides is typically not remediated forre-use or disposal because such remediation of the fluid using chemicaltreatments, for example, is cost prohibitive. Instead, the flowbackfluid is generally removed from the well site for proper treatment anddisposal. Specifically, proper disposal of fluids containing biocidesrequires removal of the biocide before the fluid can be returned to theenvironment.

Due to the scarcity of water in many remote locations, and the costassociated with transporting water to and from these well sites, itwould be beneficial if formation fluid produced from the well could beused, or flowback fluid could be reused following a service operation.However, treatment of formation fluid and flowback fluid to removebacteria is necessary for the success of many operations, such asfracturing. Hence, a need exists for a cost effective method ofdisinfecting produced fluid and flowback fluid for reuse in a well boreservicing operation, or for disposal to the environment.

SUMMARY OF THE INVENTION

In one aspect, the present disclosure relates to a hydrocarbon industryservicing fluid comprising an irradiated fluid that is biologicallyinert. The irradiated fluid may be irradiated via exposure toultraviolet light and may comprise a volume of fresh water, seawater,formation fluid, flowback fluid, or a combination thereof. Thehydrocarbon industry servicing fluid may further comprise otherconstituents. In various embodiments, the hydrocarbon industry servicingfluid comprises filling fluid, cleaning fluid, hydrostatic testingfluid, flooding fluid, flushing fluid, preservation fluid or fracturingfluid.

In another aspect, the present disclosure relates to a method ofperforming a hydrocarbon industry service operation with an irradiatedfluid that is biologically inert. In an embodiment, the fluid isirradiated with ultraviolet light. In various embodiments, thehydrocarbon industry service operation comprises injecting theirradiated fluid into a well; fracturing a formation; flooding apipeline, hydrostatically testing the pipeline, or both; or filling,cleaning, hydrostatically testing, flushing, preserving, or acombination thereof. The method may further comprise disposing of theirradiated fluid to the environment or capturing the irradiated fluidwhen the service operation is complete. In an embodiment, the methodfurther comprises re-irradiating the captured irradiated fluid toproduce a remediated fluid, and performing a service operation with theremediated fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the present invention, reference willnow be made to the accompanying drawings, wherein:

FIG. 1 is a flow schematic of a representative pipeline operationemploying an irradiation system to disinfect seawater, fresh water oranother fluid;

FIG. 2 is a flow schematic of a representative well servicing operationemploying an irradiation system to disinfect fluid to be used in afracturing operation; and

FIG. 3 is a flow schematic of a representative well servicing operationemploying an irradiation system to remediate formation fluid or flowbackfluid, either for re-use in another servicing operation or for disposal.

NOTATION AND NOMENCLATURE

Certain terms are used throughout the following description and claimsto refer to particular assembly components. This document does notintend to distinguish between components that differ in name but notfunction. In the following discussion and in the claims, the terms“including” and “comprising” are used in an open-ended fashion, and thusshould be interpreted to mean “including, but not limited to . . . ”.

As used herein, each of the terms “disinfect” and “remediate” mean torender biologically inert. Hence, to disinfect or remediate water, forexample, means to render the water biologically inert by killing themicro-organisms in the water.

As used herein, the term “pipeline” includes any line in which fluid ismoved, including any onshore or offshore flow system, such as mainlinesystems, risers, flow lines used to transport untreated fluid between awellhead and a processing facility, and flow lines used to transporttreated fluids.

In the drawings, the arrows indicate the direction of fluid flow throughthe system in a sequential operation.

DETAILED DESCRIPTION

Various embodiments of apparatus and methods for treating a fluid foruse in hydrocarbon industry applications will now be described withreference to the accompanying drawings, wherein like reference numeralsare used for like features throughout the several views. There are shownin the drawings, and herein will be described in detail, specificembodiments of irradiation systems and methods of using such systems todisinfect fluid, with the understanding that this disclosure isrepresentative only and is not intended to limit the invention to thoseembodiments illustrated and described herein. The embodiments of fluidtreatment methods and irradiation systems disclosed herein may beutilized in any type of hydrocarbon industry application, operation, orprocess where it is desired to disinfect fluid, including, but notlimited to, pipeline operations; well servicing operations; upstreamexploration and production applications; and downstream refining,processing, storage and transportation applications. It is to be fullyrecognized that the different teachings of the embodiments disclosedherein may be employed separately or in any suitable combination toproduce desired results.

FIG. 1 schematically depicts a representative pipeline operation 100utilizing an irradiation system 110, such as an ultraviolet lighttreatment apparatus, to render the fluid 120 biologically inert. Thefluid 120 may be seawater, fresh water, or another fluid, and preferablycomes from a readily available source, such as a river or the ocean. Inone embodiment, the pipeline operation 100 comprises a lift pump 150, anirradiation system 110, filters 130, a pipeline fill pump 160, and apipeline 140. The filters 130 may comprise any type of filteringapparatus to remove particles from the fluid 120, such as a sock typefilter where the fluid 120 flows through a filtering insert thatcollects particles or any other filter as described herein. The liftpump 150 and the pipeline fill pump 160 may be any type of pump suitablefor moving the fluid 120 through the irradiation system 110, filters 130and pipeline 140. The pipeline 140 may be constructed of carbon steel,an alloy, or any other material suitable for the pipelinepre-commissioning operation 100. The pumps 150, 160, the irradiationsystem 110, and the filters 130 may be containerized with other flowequipment and regulation instrumentation and mounted on a skid, therebymaking the entire apparatus portable. In an embodiment, the skid mountedequipment is electrically powered and may be operated using generatorsin remote locations.

As represented by the flow arrows, the lift pump 150 transports thefluid 120 through the filters 130, into line 180, and then into theirradiation system 110, where the filtered fluid is disinfected. Thepurpose of disinfection is to kill micro-organisms in the fluid 120. Inan embodiment, the irradiation system 110 comprises an ultraviolet lightapparatus, such as a UV-disinfection system available from HOH WaterTechnology A/S of Denmark, for example. The irradiation system 110causes the deactivation of micro-organisms, thereby effectivelydisinfecting the fluid 120. In an embodiment, the filters 130 remove asignificant quantity of debris and biological material from the fluid120 upstream of the irradiation system 110, thereby enhancing thetreatment process. In particular, the ultraviolet light source withinthe irradiation system 110 should penetrate through a filtered fluidmore effectively than through a debris-laden fluid, and some removal ofbiological material upstream of the irradiation system 110 shouldenhance the efficiency of the irradiation treatment. In contrast tountreated fluids, such as water, irradiated fluids do not as readilycorrode the wall of the pipeline 140. Further, as compared to usingchemical biocides, disinfection by irradiation is more cost effectiveand also produces an environmentally safe fluid for disposal to theenvironment. After exiting the irradiation system 110, the irradiatedand filtered fluid in line 185 is then transferred by the pipeline fillpump 160 through line 190 and into the pipeline 140 for use in pipelineoperations, such as filling and testing procedures, for example. Oncethe pipeline operations are complete, the fluid exits the pipeline 140through line 195 where the fluid may be disposed of to the environment170 without harm thereto.

One of ordinary skill in the art will readily appreciate that therepresentative pipeline operation 100 of FIG. 1 may be performedoffshore or onshore, and may include different components than the onesshown in FIG. 1. The pipeline operation 100 may involvepre-commissioning the pipeline 140, such as during installation andtesting, or post-commissioning operations, such as a repair orreplacement procedure. Although FIG. 1 shows the fluid 120 passing firstthrough the filters 130 and then through the irradiation system 110, therelative position of these treatment devices may be reversed. Forexample, the fluid 120 may be first irradiated and then filtered.

In another hydrocarbon industry application, the irradiation apparatus110 may be used to remediate produced fluid, which includes formationfluid or flowback fluid produced during well fracturing or otherservicing operations. Such remediated fluid may be reused as a well boreservicing fluid, or may be disposed of to the environment. While thefollowing discussion of FIG. 2 and FIG. 3 focuses on well fracturing, itshould be understood that the present disclosure may be used to treatwater for use in any well bore servicing fluid, or to treat such fluidsthemselves as needed to disinfect same.

FIG. 2 schematically depicts a representative well bore servicingoperation 200 utilizing the irradiation apparatus 110 to disinfect orremediate fluid supplied from a readily available source as analternative to using trucked-in water treated with chemical biocides.The water 210 from a readily available source may be fresh water,seawater, or formation water. Formation water includes water producedfrom a well on site, which may be the same or different well from thatbeing serviced. In an embodiment, this water 210 could even comprisetrucked-in water that has not been treated with chemical biocides. Thewell bore servicing operation 200 comprises a lift pump 150, filters230, the irradiation apparatus 110, a valve 260, storage 290 for gel andother fracturing fluid components, an injection pump 295, a service pump285, and a well bore 280 within which a servicing operation is beingconducted, such as fracturing, for example.

The filters 230 may comprise a variety of different types of filters,depending upon the requirements of the operation, including sock typefilters, boron removal filters, micron particle filters, activatedcharcoal filters, and/or another type of filter to make the fluid 120suitable for a well fracturing operation. In one embodiment, the filters230 comprise the filtering system depicted and described in U.S. patentapplication Ser. Nos. 11/062,963 and 11/063,307, both filed on Feb. 22,2005, and both entitled “Devices and Processes for Removal of Impuritiesfrom a Fluid Recovered from a Subterranean Environment”, assigned toHalliburton Energy Services, Inc., also the assignee of the presentapplication. Pumps 150, 285, and 295 may be any type of pump suitablefor moving the fluid 210. Valve 260 may be any type that is operable todirect fluid flow and that is compatible with the fluids in the wellbore servicing operation 200. As in the pipeline operations 100 shown inFIG. 1, the pumps 150, 285, 295; the filters 230; the irradiationapparatus 110; and the valve 260 may be containerized with theconnecting piping and other flow regulation equipment andinstrumentation and mounted on a skid, thereby making the entireapparatus portable. In an embodiment, the skid mounted equipment iselectrically powered and may be operated using generators in remotelocations.

As depicted, the water 210 from a readily available source is conveyedthrough the filters 230 by the lift pump 150. The filtered water in line240 then passes through the irradiation apparatus 110, where it isdisinfected. The filtered and irradiated fluid in line 250 then passesthrough a valve 260 where it may be diverted into a re-treatment line255 or continue on through line 265 to the fracturing operation in thewell bore 280. The filtered and irradiated fluid in line 265 is injectedwith gel and other fracturing fluid components from storage 290 viainjection pump 295, resulting in a fracturing fluid entering line 270.The service pump 285 then injects the fracturing fluid from line 270into the well bore 280 to conduct the fracturing operation. It should beunderstood that other servicing fluids can be made in a like manner, andthe additives injected via pump 295 may be selected accordingly.

Because water is often scarce at remote well site locations, it may alsobe desirable to re-use the flowback water produced by the wellfracturing or other servicing operation. FIG. 3 schematically depicts arepresentative remediation operation 300 utilizing the irradiationapparatus 110 to disinfect flowback fluid with the option to re-use theremediated fluid or dispose of it. The remediation operation 300comprises a lift pump 150, filters 230, an irradiation apparatus 110, afirst valve 380, a storage tank 310, a second valve 330, an injectionpump 295, storage 290 for gel and other fracturing fluid components, anda service pump 285.

The filters 230 may be of the same type, or a different type, as thoseused in the pipeline operation 100 or the well servicing operation 200shown in FIGS. 1 and 2, respectively. The storage tank 310 may bereplaced by a lined pit or other fluid storage reservoir. Pumps 150,285, and 295 may be of any type suitable for moving fluid and compatiblewith fluids in the remediation operation 300. Valves 330 and 380 may beany type of valve used to direct fluid flow and compatible with fluidsin the remediation operation 300. Again, all or some of the componentsshown in FIG. 3 may be containerized with other flow regulationequipment and instrumentation and mounted on a skid, thereby making theentire apparatus portable. In an embodiment, the skid mounted equipmentis electrically powered, and may be operated using generators in remotelocations.

When a fracturing operation is conducted in the well bore 280, flowbackfluid 370 is produced comprising a mixture of formation fluid andfracturing fluid. The flowback fluid 370 is lifted out of the well bore280 and conveyed through the filters 230 by the lift pump 150. Filteredfluid in line 240 then passes through the irradiation apparatus 110,where it is disinfected. The filtered and irradiated fluid in line 250is then diverted by valve 380 to the storage tank 310 via line 390 ortowards a second valve 330 via line 360. Fluid stored in the tank 310may later be circulated through re-treatment line 320 and through theirradiation apparatus 110. The fluid diverted into line 360 is directedtowards valve 330, where the filtered and irradiated fluid may bediverted through line 340 for disposal to the environment 350 or throughreturn line 265 for re-use in the fracturing operation. Alternatively,instead of re-using the filtered and irradiated fluid at the same wellsite, this fluid may be hauled by truck or transported by another meansfor re-use at a remote well site. If diverted through line 340 fordisposal, the filtered and irradiated fluid will be tested to ensurethat it is environmentally safe before it is released to the environment350, which may be a water source, e.g. river or lake; a land surface; orinjected into a disposal well. If diverted through return line 265 forre-use, gel and other frac fluid components from storage 290 may beadded to the irradiated and filtered fluid in line 265 by the injectionpump 295 to produce the frac fluid in line 270. The frac fluid is theninjected by the service pump 285 to conduct the fracturing operation inthe well bore 280.

Thus, where fluids treated with chemical biocides or untreated fluidspreviously may have been used in a hydrocarbon industry application,such as pipeline pre-commissioning or well fracturing, for example, anirradiated servicing fluid may be used instead. Irradiation may beperformed using a portable system comprising an irradiation apparatus110. These portable systems may also be used at sites where fluids mustbe disinfected, but the use of fluids treated with chemical biocides isprohibited, either due to environmental concerns or cost or both.Therefore, the irradiation apparatus may be sent to the location for anytype of hydrocarbon industry application where it is desirable todisinfect fluid.

The foregoing descriptions of specific embodiments of hydrocarbonindustry systems and applications utilizing an irradiation apparatus todisinfect fluids have been presented for purposes of illustration anddescription and are not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously many othermodifications and variations of these hydrocarbon industry systems andapplications are possible. In particular, the position of theirradiation system 110 could be varied. For example, the irradiationcould be performed prior to the fluid entering the filtering stage, orthe fluid may not require filtering at all. Also, the ultraviolet lighttreatment could be performed more than once, if necessary, with the useof additional piping. The systems 100, 200, 300 could be arrangeddifferently, and have more or less components.

Moreover, other hydrocarbon industry applications are possible. Inparticular, one of ordinary skill in the art will readily appreciatethat the fluid treatment systems disclosed herein are equally suitablefor disinfecting servicing fluids, or constituents thereof, for use inapplications such as refining and processing vessels, reactors andpipelines; production platform vessels and pipelines; storageapplications, including land-based storage tanks and tanks provided onfloating production storage and offloading facilities; and pipelinetransportation stations and facilities, as well as other applications.Such disinfected servicing fluids may be used for a wide variety ofpurposes, such as flushing out product and/or cleaning hydrocarbons fromthe walls of a vessel or pipeline, preserving a vessel or pipeline aftercleaning, or filling a storage tank, for example.

While various embodiments of hydrocarbon industry applications utilizingirradiation to disinfect fluid, as a substitute for fluids treated withchemical biocides, or untreated fluids, have been shown and describedherein, modifications may be made by one skilled in the art withoutdeparting from the spirit and the teachings of the invention. Theembodiments described herein are representative only, and are notintended to be limiting. Many variations and modifications of theinvention disclosed herein are possible and are within the scope of theinvention. Where numerical ranges or limitations are expressly stated,such express ranges or limitations should be understood to includeiterative ranges or limitations of like magnitude falling within theexpressly stated ranges or limitations (e.g., from about 1 to about 10includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13,etc.). Use of the term “optionally” with respect to any element of aclaim is intended to mean that the subject element is required, oralternatively, is not required. Both alternatives are intended to bewithin the scope of the claim. Use of broader terms such as comprises,includes, having, etc. should be understood to provide support fornarrower terms such as consisting of, consisting essentially of,comprised substantially of, etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present invention. Thus, the claims are a further description andare an addition to the preferred embodiments of the present invention.The discussion of any reference in the Background section is not anadmission that it is prior art to the present invention, especially anyreference that may have a publication date after the priority date ofthis application. The disclosures of all patents, patent applications,and publications cited herein are hereby incorporated by reference, tothe extent that they provide representative, procedural or other detailssupplementary to those set forth herein.

1. A hydrocarbon industry servicing fluid comprising: an irradiatedfluid that is biologically inert.
 2. The servicing fluid of claim 1wherein the irradiated fluid was irradiated via exposure to ultravioletlight.
 3. The servicing fluid of claim 1 wherein the irradiated fluidcomprises a volume of fresh water, seawater, formation fluid, flowbackfluid, or a combination thereof.
 4. The servicing fluid of claim 1further comprising other constituents.
 5. The servicing fluid of claim 1wherein the servicing fluid comprises: filling fluid, cleaning fluid,hydrostatic testing fluid, flooding fluid, flushing fluid, preservationfluid or fracturing fluid.
 6. A method comprising: performing ahydrocarbon industry service operation with an irradiated fluid that isbiologically inert.
 7. The method of claim 6 wherein the fluid wasirradiated with ultraviolet light.
 8. The method of claim 6 wherein theservice operation comprises injecting the irradiated fluid into a well.9. The method of claim 6 wherein the service operation comprisesfracturing a formation.
 10. The method of claim 6 wherein the serviceoperation comprises flooding a pipeline, hydrostatically testing thepipeline, or both.
 11. The method of claim 6 wherein the serviceoperation comprises filling, cleaning, hydrostatically testing,flushing, preserving, or a combination thereof.
 12. The method of claim6 further comprising: disposing of the irradiated fluid to theenvironment when the service operation is complete.
 13. The method ofclaim 6 further comprising: capturing the irradiated fluid when theservice operation is complete.
 14. The method of claim 13 furthercomprising: re-irradiating the captured irradiated fluid to produce aremediated fluid; and performing a service operation with the remediatedfluid.